LOCATION.--Lat
40°35'36", long 73°35'03" referenced to North
American Datum of 1927, Nassau County, NY, Hydrologic Unit 02030202, at
Town of Hempstead East Marina, 750 ft east of Loop Parkway Bridge, in
Point Lookout. Water-quality monitor at site 100 ft north.PERIOD OF RECORD.--December 1997 to current year. January 1974
to June 1994, in files of Town of Hempstead Department of Conservation
& Waterways. Precipitation, wind speed and direction, air
temperature, relative humidity, and barometric pressure records for
March 1998 to current year, and solar radiation records for August 2004
to current year, are unpublished and available in files of the
Geological Survey.GAGE.--Water-stage recorder. Datum of gage is NGVD of 1929.
January 1974 to June 1994, water-stage recorder at site 150 ft
northeast.REMARKS.--Records excellent, except those for Oct. 1-20, 22-29,
and June 16 to Sept. 2, which are good; and those estimated with MISTE
for June 11, which are poor. Periods of missing record were estimated
with MISTE using a linear regression with 01310521 and 01311143.
Satellite and telephone elevation, precipitation, and wind speed and
direction telemeters at station. Telephone telemeter for air
temperature, relative humidity, barometric pressure, and solar
radiation parameters at station.EXTREMES FOR PERIOD OF RECORD.--Maximum elevation, 9.90 ft, Oct.
29, 2013; minimum elevation, -4.28 ft, Mar. 9, 2005.EXTREMES OUTSIDE PERIOD OF RECORD.--Storm tide of Sept. 27,
1985, reached an elevation of 7.3 ft, from information provided by Town
of Hempstead Department of Conservation & Waterways. Storm tide of
Dec. 11, 1992, reached an elevation of 7.3 ft, from high-water mark at
site 4.0 mi west. Minimum elevation recorded, -4.9 ft, Jan. 11, 1978,
Mar. 16, 1980, from information provided by Town of Hempstead
Department of Conservation & Waterways.EXTREMES FOR CURRENT YEAR.--Maximum elevation, 9.90 ft, Oct. 29;
minimum elevation, -2.84 ft, Jan. 10.PERIOD OF RECORD1.--October 2004 to current year.
Water temperature records for March 1998 to September 2004, and
sampling depth records for October 2004 to current year are unpublished
and available in files of the Geological Survey.PERIOD OF DAILY RECORD1.--
WATER TEMPERATURE: October 2004 to current year.
SALINITY: October 2004 to current year.
DISSOLVED OXYGEN: October 2004 to current year.
TURBIDITY: October 2004 to current year.
CHLOROPHYLL: August 2006 to current year.INSTRUMENTATION1.--Water-quality monitor provides
12-minute-interval readings collected from 1.6 ft above bottom. October
2004 to February 2005, water-quality monitor provided 6-minute-interval
readings. Salinity record computed from specific-conductance
readings.REMARKS1.--Telephone telemeter for water temperature,
specific conductance, dissolved oxygen, turbidity, chlorophyll, and
sampling depth parameters at station. Interruptions of record were due
to malfunction of water-quality monitor or sensors.
WATER TEMPERATURE: Records excellent.
SALINITY: Records excellent, except those for Apr. 11 to June 11 and
Sept. 12-25, which are good; and Jan. 2, which are fair.
DISSOLVED OXYGEN: Records excellent, except those for Dec. 28, June 14
to July 7, and Aug. 3-14, which are good; for Feb. 28 to Mar. 2, July
8, and Aug 15-25, which are fair; and those for Mar. 3 to Apr. 5, July
9-12,and Aug. 26-29, which are poor.
TURBIDITY: Records excellent, except those for Oct. 1-6, Nov. 15-27,
Dec. 21-26, June 12-13, July 7-10 and Aug. 3-4, which are good; and for
Oct. 7-13, Nov. 28-30, and June 14-16, which are fair; and for Oct.
14-18, Feb. 28 to Apr. 3, May 19-20, July 11-14, Aug. 5-8, and 14,
which are poor.
CHLOROPHYLL: Records excellent, except those for Oct. 1-14, 18, May 12,
June 12-13, July 6-7, Aug. 10, 15, 17-21, and Sept. 5-8, which are
good; for Oct. 15-17, May 10-11, 14-23, June 14, July 8, Aug. 22-27,
Sept. 9-12, 14-17, and 19-21,which are fair; and those for Nov. 30 to
Apr. 12, May 13, May 24 to June 11, June 15-18, July 9-13 Aug. 28-29,
Sept. 13, 18 and 22-25, which are poor. Part of the record for June 19
to July 5, and July 14-31 exceeded the maximum allowable limits and was
deleted.EXTREMES FOR PERIOD OF RECORD1.--WATER TEMPERATURE:
Maximum, 27.9 °C, July 18, 2013, Aug. 4, 2012; minimum, -1.7 °C, Jan.
23, 24, 28, 2005.
SALINITY: Maximum, 34.6 psu, Feb. 9, 2010; minimum, 21.4 psu, Oct. 14,
15, 2005.
DISSOLVED OXYGEN: Maximum, 15.9 mg/L, Mar. 1, 2007; minimum, 1.9 mg/L,
June 24, 2008.
TURBIDITY: Maximum, 410 FNU, Sept. 14, 2013; minimum, <0.1 FNU
several days each year 2005-2011.
CHLOROPHYLL: Maximum, 100 ug/L, Apr. 11, 2010, Mar. 12, 2012, but may
have been higher during period of missing record; minimum, <0.1 ug/L
many days each year 2006-08, June 9, 10, 2009.EXTREMES FOR CURRENT YEAR1.--WATER TEMPERATURE:
Maximum, 27.9 °C, July 18; minimum, 2.8 °C, Dec. 31.
SALINITY: Maximum, 33.9 psu, several times in Mar. and Apr.; minimum,
26.6 psu, June 8.
DISSOLVED OXYGEN: Maximum, 15.7 mg/L, Mar. 27; minimum, 2.6 mg/L, Aug.
27.
TURBIDITY: Maximum, 410 FNU, Sept. 14; minimum, 0.7 FNU, Sept.
27.
CHLOROPHYLL: Maximum, 76 ug/L, June 9; minimum, 0.1 ug/L, Oct. 30-31,
Nov. 9, 12, and 17.1 Water-Quality RecordsDerived from NY Annual Water-Data Report 2012

Elevation observations and tidal predictions for this
station are reported to NGVD 1929. To convert data to NAVD 1988
subtract 1.13 ft. To convert data to MHHW datum subtract 3.53 ft.
To convert data to MLLW datum add 1.10 ft. These corrections vary
from site to site.

NGVD 1929
is the National Geodetic Vertical Datum of 1929, formerly called
"mean sea level" or "Sea Level Datum of
1929." NGVD 1929 was a general adjustment of the first-order
level nets fit to mean sea level at 26 tide gages in the US and
Canada.NAVD 1988
is the North American Vertical Datum of 1988, which is a geodetic
datum derived from a general adjustment of the first-order level
nets fit to 1 tide gage in eastern Canada.MHHW is
mean higher high water, which is a site-specific datum determined
by averaging the highest of the 2 high tides that occur each day
over a 19-year tidal epoch. For tide gages with less than 19
years of record, this datum is estimated by correlation with
long-term tide gages.MLLW is
mean lower low water, which is a site-specific datum determined
by averaging the lowest of the 2 low tides that occur each day
over a 19-year tidal epoch. For tide gages with less than 19
years of record, this datum is estimated by correlation with
long-term tide gages.